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Prof. Frank Koppens

ICFO - The Institute of Photonic Sciences (Barcelona)

Friday, February 1st, 2013 at 11:00:00 AM  

Conference room Querzoli - LENS - via Nello Carrara 1 - Sesto Fiorentino (Florence)

Enrico Fermi Colloquium

Published on-line at 10:03:55 AM on Monday, January 28th, 2013

Graphene nano-photonics and carrier dynamics

A look at the new and strongly emerging field of graphene nano-photonics.

Graphene, a two-dimensional sheet of carbon atoms, has recently emerged as a novel material with unique electrical and optical properties, with great potential for novel opto-electronic applications, such as ultrafast photo-detection, optical switches, strong light-matter interactons.

In this talk I will review the new and strongly emerging field of graphene nano-photonics. In particular, I will show how to exploit graphene as a host for guiding, switching and manipulating light and electrons at the nanoscale (see 10.1038/nature11254 and 10.1021/nl201771h). This is achieved by exploiting surface plasmons: surface waves coupled to the charge carrier excitations of the conducting sheet. Due to the unique characteristics of graphene, light can be squeezed into extremely small volumes and thus facilitate strongly enhanced light-matter interactions.

Additionally, I will discuss novel types of hybrid graphene photodetectors (10.1038/nnano.2012.60) and new excitating results on carrier dynamics and carrier multiplication in graphene. By studying the ultrafast energy relaxation of photo-excited carriers after excitation with light of varying photon energy, we find that electron-electron scattering dominates the energy relaxation cascade rather than electron-phonon interaction (arXiv:1112.4730). This singles out graphene as a promising material for highly efficient broadband extraction of light energy into electronic degrees of freedom, enabling a new class of high-efficiency optoelectronic and photovoltaic applications.

[video=720 540]a20130201_koppens[/video]

Klein colloquium by Dr. Letizia Allegra Mascaro: "Human Brain Project: the LENS contribution".

[video=720 540]b20130201_mascaro[/video]

For further informations, please contact Dr. Costanza Toninelli.